Method and apparatus for performing ophthalmic procedures removing undesirable features using laser energy

ABSTRACT

A method and system perform an ophthalmic procedure on an eye having an optical path from the lens to the retina. An image of at least part of the eye is received in a data processing unit. The image includes the optical path. The data processing unit determines keep out zone(s) and identifies undesirable feature(s) based on the image. The keep out zone(s) include the retina. The data processing unit also selects one of the undesirable feature(s) for removal. At least part of the undesirable feature is outside of the keep out zone(s). Confirmation for removal of the undesirable feature is received in the data processing unit. In response to receiving the confirmation, a control unit controls a laser to perform laser removal the at least the portion of the undesirable feature without targeting any portion of the keep out zone(s).

This application is a divisional application of U.S. Non-Provisionalpatent application Ser. No. 15/225,146 titled “METHOD AND APPARATUS FORPERFORMING OPHTHALMIC PROCEDURES REMOVING UNDESIRABLE FEATURES USINGLASER ENERGY,” filed on Aug. 1, 2016, whose inventor is Tammo Heeren,which is hereby incorporated by reference in its entirety as thoughfully and completely set forth herein.

FIELD

This present disclosure relates generally ophthalmic surgery and, moreparticularly, to a method and apparatus for performing ophthalmicprocedures removing undesirable features using laser energy.

BACKGROUND

The human eye sees by transmitting and refracting light through a clearouter portion of the eye called the cornea, transmitting the lightthrough an aperture in the iris known as the pupil, focusing the lightvia a lens, transmitting the focused light through the vitreal cavityand onto the retina. The quality of the focused image depends on manyfactors including but not limited to the size, shape and length of theeye, the quality of the vitreous humor, and the shape and transparencyof the cornea and lens. Trauma, age, disease and/or another malady maycause an individual's vision to degrade.

For example, undesirable features within the vitreal cavity mayadversely vision. Vitreous opacities, otherwise known as vitreousfloaters, are one type of undesirable feature. Vitreous opacities arefree to move within the vitreous humor of the vitreal cavity. Whensufficiently large and/or dense and within the optical path between thepupil and the retina, such vitreous opacities may obscure anindividual's vision. One remedy for vitreous opacities is removal. Insome cases, a small gauge vitrectomy may be performed. The small gaugevitrectomy may be performed by inserting a narrow gauge line into thevitreal cavity and removing a portion of the vitreous humor containingthe vitreous opacity. Alternatively, the vitreous opacity may be removedvia the application of laser energy. In such a method, a physician usesa slit lamp to view the posterior portion of the eye and localize thevitreous opacities. The physician then manually aims and fires thelaser. The laser energy vaporizes at least part of a vitreous opacity.This procedure is repeated until the vitreous opacity is removed. Theentire procedure is repeated for each vitreous opacity, until thevitreal fluid is deemed sufficiently clear.

Although the vitreous floaters may be removed, there are drawbacks.Small gauge vitrectomies are invasive, require an operating visit andcarry the attendant risks. The use of laser energy is non-invasive andavoids these drawbacks. However, aiming of the laser may be difficult.Because the physician views the vitreal cavity along the optical path,it may be difficult to determine the depth of the location of theretina, the vitreous opacity or other relevant features. Consequently,there is a danger of missing the vitreous opacity and/or injuring theeye. Application of laser energy may also result in movement of thevitreous opacities. Thus, the physician re-aims the laser after eachapplication of laser energy. This may consume a large amount of time.Therefore, the use of laser energy may involve multiple out-patientvisits, each of which may be hours long. Such a procedure is burdensomeon the patient and the physician.

Accordingly, what is needed is a mechanism for improving the removal ofundesirable features in the vitreal cavity.

BRIEF SUMMARY OF THE INVENTION

A method and system perform an ophthalmic procedure on an eye having anoptical path from the lens to the retina. An image of at least part ofthe eye is received in a data processing unit. The image includes theoptical path. The data processing unit determines keep out zone(s) andidentifies undesirable feature(s) based on the image. The keep outzone(s) include the retina. The data processing unit also selects one ofthe undesirable feature(s) for removal. At least part of the undesirablefeature is outside of the keep out zone(s). Confirmation for removal ofthe undesirable feature is received in the data processing unit. Inresponse to receiving the confirmation, a control unit controls a laserto perform laser removal the at least the portion of the undesirablefeature without targeting any portion of the keep out zone(s).

According to the method and system disclosed herein, a physician may bebetter and more easily able to remove undesirable features such asvitreous opacities without surgery.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings in which likereference numerals indicate like features and wherein:

FIG. 1 is a flow chart depicting an exemplary embodiment of a method forperforming an ophthalmic procedure that removes undesirable featuresusing laser energy;

FIG. 2 is a block diagram of an exemplary embodiment of an ophthalmiclaser apparatus for removing undesirable features from the vitrealcavity using laser energy;

FIG. 3 is a flow chart depicting an exemplary embodiment of a method forperforming an ophthalmic procedure removing undesirable features such asvitreous opacities using laser energy; and

FIGS. 4A-4L depict exemplary embodiments of images of the eye duringnon-surgical removal of undesirable features such as vitreous opacities.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The exemplary embodiments relate to mechanisms for removing undesirablefeatures in the vitreal cavity, such as vitreous floaters. The followingdescription is presented to enable one of ordinary skill in the art tomake and use the invention and is provided in the context of a patentapplication and its requirements. Various modifications to the exemplaryembodiments and the generic principles and features described hereinwill be readily apparent. The exemplary embodiments are mainly describedin terms of particular methods and systems provided in particularimplementations. However, the methods and systems will operateeffectively in other implementations. Phrases such as “exemplaryembodiment”, “one embodiment” and “another embodiment” may refer to thesame or different embodiments as well as to multiple embodiments. Theembodiments will be described with respect to systems and/or deviceshaving certain components. However, the systems and/or devices mayinclude more or less components than those shown, and variations in thearrangement and type of the components may be made without departingfrom the scope of the invention. Further, although specific blocks aredepicted, various functions of the blocks may be separated intodifferent blocks or combined. The exemplary embodiments will also bedescribed in the context of particular methods having certain steps.However, the method and system operate effectively for other methodshaving different and/or additional steps and steps in different ordersthat are not inconsistent with the exemplary embodiments. Thus, thepresent invention is not intended to be limited to the embodimentsshown, but is to be accorded the widest scope consistent with theprinciples and features described herein.

The method and system are also described in terms of singular itemsrather than plural items. One of ordinary skill in the art willrecognize that these singular terms encompass plural. For example, animage may include one or more images. In certain embodiments, the systemincludes one or more processors and a memory. The one or more processorsmay be configured to execute instructions stored in the memory to causeand control the process set forth in the drawings and described below.As used herein, a processor may include one or more microprocessors,field-programmable gate arrays (FPGAs), controllers, or any othersuitable computing devices or resources, and memory may take the form ofvolatile or non-volatile memory including, without limitation, magneticmedia, optical media, random access memory (RAM), read-only memory(ROM), removable media, or any other suitable memory component. Memorymay store instructions for programs and algorithms that, when executedby a processor, implement the functionality described herein withrespect to any such processor, memory, or component that includesprocessing functionality. Further, aspects of the method and system maytake the form of an entirely hardware embodiment, an entirely softwareembodiment (including firmware, resident software, micro-code, etc.) oran embodiment combining software and hardware aspects. Furthermore,aspects of the method and system may take the form of a softwarecomponent(s) executed on at least one processor and which may beembodied in one or more computer readable medium(s) having computerreadable program code embodied thereon.

A method and system perform an ophthalmic procedure on an eye having anoptical path from the lens to the retina. An image of at least part ofthe eye is received in a data processing unit. The image includes theoptical path. The data processing unit determines keep out zone(s) andidentifies undesirable feature(s) based on the image. The keep outzone(s) include the retina. The data processing unit also selects one ofthe undesirable feature(s) for removal. At least part of the undesirablefeature is outside of the keep out zone(s). Confirmation for removal ofthe undesirable feature is received in the data processing unit. Inresponse to receiving the confirmation, a control unit controls a laserto perform laser removal the at least the portion of the undesirablefeature without targeting any portion of the keep out zone(s).

FIG. 1 is a flow chart depicting an exemplary embodiment of a method 100for performing an ophthalmic procedure that removes undesirable featureswithin the vitreal cavity of the eye. For simplicity, some steps may beomitted, interleaved, performed in another order and/or combined. Themethod 100 may include executing instructions on one or more processors.Further, the method 100 is described in the context of a non-invasiveprocedure. However, the method 100 may be extended to invasiveprocedures including but not limited to use in connection withophthalmic surgery. The method 100 is performed by an ophthalmic laserapparatus including a data processing unit and a controller.

At least one image of at least a portion of the eye is received in thedata processing unit, via step 102. Receipt of the image(s) in step 102may include receiving image data from a separate imaging system orcapturing the image by a portion of the system carrying out the method100. Step 102 need not include rendering the image for the physician.Instead, step 102 includes obtaining data for the eye. The image(s)include the optical path of the eye. In some embodiments, the image(s)may be two-dimensional. In other embodiments, three-dimensionalimage(s), such as optical coherence tomograph(s) (OCTs), may be used.Thus, the image(s) may include the volume of the eye or simply across-section of the eye. In some embodiments, video or other mechanismfor showing the progression of time may be part of the image(s) receivedin step 102.

Keep out zones are determined by the data processing unit based on theimage data, via step 104. A keep out zone is a region of the eye inwhich the laser is desired not to be aimed. The keep out zones assist inensuring that more delicate regions of the eye are not heated by thelaser and, therefore, remain undamaged. Keep out zones include, forexample, the retina. Step 104 may include using other patient data inaddition to the image data to determine the keep out zone. For example,if the size of the patient's eye is already known, this information maybe used in step 104. Step 104 may thus include identifying structuresand setting a keep out zone to be the structure and a region within aparticular distance of the structure. Thus, step 104 may includeidentifying the location of the retina from the image and/or other dataand setting the keep out zone to include the retina and the regionwithin two millimeters of the retina. In some embodiments, the keep outzone may include the retina and the region within only one millimeter ofthe retina. Other distances and/or other structures may be included inother keep out zones.

The physician may be allowed to adjust the size and/or location of thekeep out zone as part of step 104. For example, the keep out zonecorresponding to the retina that is determined by the data processingunit may include retina and the region within 0.5 millimeters of theretina. The physician may be allowed to reduced or increase the size ofthe keep out zone. Thus, the physician may be able to set the keep outzone for the retina as including the retina and the region within 0.25millimeter of the retina. The physician may also be allowed to move thekeep out zone to include a different part of the retina. However, theremay also be a minimum distance beyond which the physician is not allowedto change the size or position of the keep out zone. In the exampleabove, the physician may be prevented from shrinking the keep out zonesuch that the keep out zone is smaller than the retina.

The undesirable features within the vitreal cavity are identified by thedata processing unit based on the image data, via step 106. Step 106includes identifying a set of locations corresponding to the undesirablefeatures. In some embodiments, only those undesirable features whichintersect the optical path are detected in step 106. In otherembodiments, all undesirable features that can be found based on theimage data are identified. For example, vitreous floaters, or vitreousopacities, may be identified in step 106. As used herein, a vitreousfloater is synonymous with a vitreous opacity. A vitreous opacity may beany feature within the vitreous humor that has an opacity greater than athreshold and a size greater than a size threshold. Default thresholdsmay be provided, but may be adjusted by the user. In some embodiments,the threshold may be as low as zero. In such embodiments, any deviationfrom a background opacity and/or having any size may be identified as anundesirable feature. As part of step 106, the undesirable features mayalso be ranked based on certain characteristics. For example, the size,location, density and/or shape of the vitreous opacity may be used torank the vitreous opacities. These characteristics may have the sameweight or different weights. In some embodiments, size is given agreater weight than location and location is given a greater weight thandensity. Opacities that are larger, are closer to or have a largersection within the optical path and/or are more dense/more opaque mayhave a higher rank. As used herein, a higher ranked vitreous opacity isa vitreous opacity is more desired to be removed.

One of the undesirable features is selected by the data processing unitfor removal, via step 108. At least part of this undesirable feature isoutside of the keep out zone(s). Consequently, the undesirable featuremay be removed by laser energy. In some embodiments, step 108 includesselecting the highest ranked (e.g. largest, most obstructive of theoptical path and/or most dense). In embodiments in which the ranking isnot performed as part of step 106, the ranking may be performed as partof step 108. Thus, the undesirable features may be set for removal inorder from most desired to be removed to least important for removal.

A confirmation for removal of the undesirable feature is received in thedata processing unit, via step 110. In some embodiments, step 110 isoptional. Step 110 may include querying the physician performing theprocedure and receiving a response. For example, a “REMOVE” button maybe provided on the display of a user interface (U/I). In response to thephysician selecting and clicking on the REMOVE button, the confirmationis received in step 110. If no confirmation is received, then the methodmay return to step 102 or the physician may be allowed to select adifferent undesirable feature for removal via the U/I. Confirmation ofthe removal is desired to aid in ensuring the safety of the patient.

In response to receiving the confirmation, the laser is controlled bythe controller to automatically perform removal of at least part of theundesirable feature, via step 112. For example, step 112 may includeautomatically aiming the laser at location(s) within the selectedundesirable feature, turning the laser on for a particular time and thenturning the laser off (i.e. firing the laser). The laser is aimed instep 112 such that the target for the focus of the laser energy isoutside of the keep out zones. Heating from the laser may be mostintense at this target. Step 112 may also include setting the laserpower and/or time based on the location targeted. For example, if theregion at which the laser is aimed is near a keep out zone, a lowerenergy or shorter application of laser energy might be used.Consequently, even if there is some heating of the keep out zone, itwill be relatively small.

Performing the laser removal in step 112 may include further substeps.For example, if the undesirable feature is sufficiently large and/ornear the keep out zone, then multiple applications of laser energy mightbe required for removal. Further, the undesirable feature may not onlychange shape, but also move as portions of the undesirable feature arevaporized. Step 112 may then include re-imaging the eye, tracking theundesirable feature and reapplying the laser energy. Tracking theundesirable feature may include comparing the image(s) of the eye takenafter the laser energy is applied with those taken before the laserenergy is applied and matching the identified undesirable featuresidentified in the later image(s) with those in the previous image(s)based on size, location, shape, and/or other criteria. These processesmay be performed by the data processing unit of the ophthalmic laserapparatus. The undesirable feature selected in step 108 is tracked bythe ophthalmic laser apparatus so that the laser energy tends to beapplied to the same undesirable feature throughout step 112. Thus, steps102 through 106 may be repeated as part of step 112. This processcontinues until the undesirable feature is considered to be removed(untrackable or missing). Some or all of the method 100 may optionallybe repeated to remove the remaining undesirable features.

Using the method 100, a physician may be able to more quickly and easilyremove undesirable features such as vitreous floaters, from the eye.Instead of viewing the eye, manually aiming the laser and turning thelaser on or off, the physician may simply confirm removal. Because theimaging and laser removal may be performed automatically, the time takento remove each floater may be greatly reduced. Consequently, the burdenon both the physician and patient may be diminished. Because keep outzones may be automatically determined and respected by the laser removalprocess, the method 100 may be safer for the patient. Further, themethod 100 may be performed non-invasively. Consequently, the removal ofundesirable features via a laser may be improved.

FIG. 2 is a block diagram of an exemplary embodiment of an ophthalmiclaser apparatus 200 for assisting a physician removing undesirablefeatures from the vitreal cavity. The ophthalmic laser apparatus 200includes an imaging system 210, laser 212, a controller 220, a dataprocessing unit 230, a user interface (U/I) 240 and a data store 250including any patient data, parameters and other information. Forsimplicity, only some components are shown. In addition, the componentsdepicted in FIG. 2 may be packaged together in a single apparatus.Alternatively, certain components, such as portions of imaging system,laser and data processing, may be implemented separately. Further, thecomponents may be implemented in hardware and/or software. Also shown inFIG. 2 is the sample eye 202 to be interrogated. The method 100 may beimplemented using the system 200.

The imaging system 210 may include a camera and/or other image capturedevice that may be managed using the controller 220. In someembodiments, step 102 may include the controller 220 managing thefocusing and capture of the image(s) by the imaging system 210. Thecamera may or may not include a microscope or other magnification thatallows for enhanced detail. In other embodiments, other components maybe used in for the imaging system 210. Such imaging systems 210 may ormay not provide three-dimensional data for the eye. In some embodiments,video camera(s) or other mechanism for showing the progression of timemay be part of the image(s) received in step 102. Further, theresolution of the imaging system 210 is sufficiently to allow therelevant features of the eye to be determined.

The laser 212 is used to vaporize portions of the undesirable features.For example, the laser 212 may be a YAG laser. The U/I 240 allows outputto be provided to the physician and input to be received from thephysician. For example, the physician may indicate confirmation in step110 of the undesirable feature selected for removal via the U/I 240. TheU/I 240 provides this confirmation to the data processing unit 230. TheU/I 240 may also include a display for rendering image(s) of the eye orproviding other visual feedback to the physician.

The data processing unit 230 receives image data from the imaging system210 in step 102. The data processing unit 230 also performs steps 104,106, 108 and 110. In some embodiments, the data processing unit 230 alsoaccesses the data store 250 in order to process the image data providedin step 102.

The controller 220 communicates with the laser 212, imaging system 2120and data processing unit 230 and user interface 240. The controller 220manages the laser 212 and imaging system 210. For example, the control220 may focus the camera or other image capture device in the imagingsystem 210, control capture of the image(s), aim the laser 212 and turnthe laser 212 on/off. Using the ophthalmic laser apparatus 200,therefore, the method 100 may be implemented. One or more of thebenefits of the method 100 may thus be achieved.

FIG. 3 is a flow chart depicting an exemplary embodiment of a method 150for performing an ophthalmic procedure that removes undesirablefeatures. For simplicity, the method 150 is described in the context ofremoval of vitreous opacities, or floaters. Some steps may be omitted,interleaved, performed in another order and/or combined. The method 150may include executing instructions on one or more processors. Further,the method 150 is described as being performed by the system 200.However, the method 150 may be performed by other apparatuses (notshown). The method 150 may be performed non-invasively. In otherembodiments, the method 150 may be incorporated in to an ophthalmicsurgical procedure.

FIGS. 4A-4L depict exemplary embodiments of images/image data 300 of theeye during the method 150. FIGS. 4A-4L are not to scale. The images 300may or may not be rendered and shown to the physician via the U/I 240. Aparticular patient, condition or response is not intended to be shown inFIGS. 4A-4L. In addition, the images actually captured using the method150 may not correspond to the orientation shown. For example, imagescaptured by a camera pointed into the pupil 308 may capture a vieworthogonal to that shown in FIGS. 4A-4L. Images captured by an OCTindicate the volume of the eye. Thus, such OCT images include but arenot limited to the views shown in FIGS. 4A-4L. FIGS. 4A-4L are,therefore, for explanatory purposes only and not intended to represent aspecific image.

Image(s) of at least a portion of the eye are captured, via step 152.Step 152 may include the controller 220 managing the imaging system 210to capture the image. As part of step 152, the image data for theimage(s) are received by the data processing unit 230. Thus, at leastpart of step 152 is analogous to step 102. The image capture and imagedata may be for two dimensional or three dimensional views of the eye.FIG. 4A depicts an image 300 of the eye that could be consideredcaptured in step 152. The cornea 302, lens 304, iris 306, pupil 308,vitreal cavity 310 and retina 320 are indicated for the purposes ofexplanation. Also shown are vitreous opacities 330, 332 and 334.Although the entire eye is shown in FIG. 4A, in other embodiments, theimages capture data for only a portion of the eye. For example, only theoptical path and surrounding region might be imaged.

Keep out zones are determined by the ophthalmic laser apparatus based onthe image data and any additional data for the patient, via step 154.Step 154 is analogous to step 104. Step 154 may thus include identifyingstructures such as the retina 320 and setting a keep out zone to be thestructure and a region within a particular distance of the structure.The physician may be allowed to adjust the size and/or location of thekeep out zone 322 as part of step 154. For example, the keep out zone322 might be made thinner such that a region a smaller distance from theretina 320 is included. However, there may also be a minimum distancebeyond which the physician is not allowed to change the size or positionof the keep out zone. For example, the keep out zone may be required toinclude the portion of the retina 320 already within the keep out zoneand a region within some small distance of this portion of the retina320. FIG. 4B depicts the information added in step 154. Thus, theoptical path 312 is indicated by dotted lines. In addition, a keep outzone 322 indicated by dashed lines has also been determined. The keepout zone 322 includes a portion of the retina 320 in and around theoptical path 312 and a region a particular distance anterior of theretina 320. Other keep out zones (not shown in FIG. 4B for simplicity)may be provided in step 154.

The vitreous opacities are identified by the data processing unit 230based on the image data, via step 156. Step 156 may also utilizeinformation in the data store 250. Step 156 is thus analogous to step106. Thus, the vitreous opacities 330, 332 and 334 are defined in step156. In some embodiments, the vitreous opacity 334 might be omitted fromthe vitreous opacities determined in step 156 because the vitreousopacity may be sufficiently small and/or sufficiently far from theoptical path 312 to be considered by the method 150. However, in otherembodiments, the vitreous opacity 334 is included. Step 156 may alsoinclude ranking the vitreous opacities 330, 332 and 334 based on size,location and density. The ranking is presumed to be, in order, 332, 334and 336.

One of the vitreous opacities 330, 332, 334 is selected by the dataprocessing unit 230 for removal, via step 158. Step 158 is analogous tostep 108. In the embodiment shown, the vitreous opacity 330 is selectedfor removal because it was ranked first in step 156. In embodiments inwhich the ranking is not performed as part of step 156, the ranking maybe performed as part of step 158.

A confirmation for removal of the undesirable feature is received by thedata processing unit 230, via step 160. Step 160 is analogous to step110 optional. Step 140 may include receiving input from a physician viathe U/I 240, response. If no confirmation is received, then the methodmay return to step 152 or the physician may be allowed to select adifferent undesirable feature for removal via the U/I.

In response to receiving the confirmation, the laser 212 is controlledby the controller 210 to automatically performed removal of at leastpart of the vitreous opacity 330. In order to do so, steps 162, 163,164, 166, 168 and 170 may be used. For example, the controller 220automatically aims the laser 210 at location(s) within the selectedvitreous opacity 330 and outside of the keep out ozone 222, via step162. If a sufficient amount of the vitreous opacity 330 selected forremoval were in the keep out zone 322, then the physician may be allowedto override the method 150 and focus the laser 210 within the keep outzone 322, via step 163. FIG. 4C depicts the image 300 with the laseraimed at target 350. This target 350 is within the selected vitreousopacity 330 and outside of the keep out zone 322. Further, the target350 is within the optical path 312, which may be desirable. As a result,the portion of the vitreous opacity 330 within the optical path 312 andmore likely to affect vision may be removed first.

Once aimed, the laser 210 may be fired using the controller 220 to turnthe laser 210 on and off, via step 164. As a result, at least a portionof the selected vitreous opacity 330 is vaporized.

The eye is optionally reimaged, via step 166. Step 166 is analogous tostep 152. FIG. 4D depicts the image 300 of the eye after step 166 isperformed. Thus, the vitreous opacity 330′ is smaller, has changed shapeand may have moved. It is determined whether the remaining portion ofthe selected vitreous opacity 330′ may be tracked. Tracking may includecomparing the image(s) of the eye taken after the laser energy isapplied in step 164 with those taken in step 152 and matching the size,location, shape and/or other features of the vitreous opacities. As canbe seen in FIGS. 4B and 4D, the vitreous opacity 330′ corresponds to thevitreous opacity 330 and is still sufficiently large for tracking. Theselected vitreous opacity 330′ is thus tracked in step 170. Stateddifferently, the shape and location of the vitreous opacity 330′ may besaved. Step 162 may then be returned to. Steps 162, 164, 166, 168 and170 may be iteratively performed until the vitreous opacity 330′ may nolonger be tracked.

Thus, FIG. 4E depicts the target 350′ for the vitreous opacity 330′determined on the next (second) iteration of step 162. FIG. 4F depictsthe target 350″ on the third iteration of the method 150. Thus, thevitreous opacity 330″ is even smaller. The target 350″ is both at leastpartially within the vitreous opacity 330″ and outside of the keep awayzone 322. FIG. 4G depicts the image after the vitreous opacity 330′″after the third iteration of the fining of the laser in step 164. Thevitreous opacity 330′″ can no longer be tracked. Thus, the vitreousopacity 330′″ may be considered removed.

Because it is determined in step 168 after three iterations that thevitreous opacity 330′″ can no longer be tracked, it is determined instep 172 whether there may be additional vitreous opacities to beremoved. As can be seen in FIG. 4G, vitreous opacities 332 and 334remain. Thus, step 154 is returned to using the image data from step166. Alternatively, step 152 may be returned to in order to obtain moreimage data.

Thus, steps 154 through 172 may be repeated. As can be seen in FIG. 4G,the next vitreous opacity 332 is targeted in step 162. The target 360for the vitreous opacity 443 is both within the vitreous opacity 332 andoutside of the keep out zone 322. FIG. 4H depicts the image after step164 is performed for the vitreous opacity 332. Thus, only a portion ofthe vitreous opacity 332′ remains. However, substantially all of thevitreous opacity 332′ is in the keep out zone 322. In some embodiments,this would complete removal of the vitreous opacity 332′. However, FIG.4I depicts a target 360′ on the vitreous opacity 332′ and within thekeep out zone 320. This is because the physician has used step 163 tooverride the requirement that the laser 210 be focused outside of thekeep out zone 322. The laser 210 is fired by the controller 220 in step164. FIG. 4J depicts an image of the eye taken in step 166. Thus, thevitreous opacity 332′ has been completely removed.

In some embodiments, this might complete the method 150 because vitreousopacities within the optical path 312 have been removed. However, inthis case, removal of the remaining identified and trackable vitreousopacity 334 is desired. Thus, the method 150 repeats and the physicianconfirms removal of vitreous opacity 334 in the next iteration of step160. FIG. 4K depicts the image 300 after the controller aims the laserin step 152. Thus, target 370 is shown. The target 370 for the laser 210is within the vitreous opacity 334 and outside of the keep out zone 322.The laser 210 may then be fired in step 164. The steps 162, 163, 164,166, 168 and 170 may be repeated until the vitreous opacity 334 is nottrackable and removed.

FIG. 4L depicts an image of the eye after removal of the vitreousopacity 334. The image 300 may be captured after the last iteration ofstep 166 for the vitreous opacity 334. Thus, step 168 determines thatthe opacity (not present in FIG. 4L) is not trackable. Step 172 may alsodetermine that there are not more vitreous opacities. This is becausethe opacity 330″ may be sufficiently small that it does not meet any ofthe thresholds set for localizing opacities. Thus, the method 150completes.

Using the method 150, a physician may be able to more quickly and easilyremove vitreous floaters, from the eye. Instead of viewing the eye,manually aiming the laser and turning the laser on or off, the physicianmay simply confirm removal in step 160 and optionally change or overridekeep out zones in steps 154 and/or 163. The system 200 may perform someor all of the method 150. Thus, the burden on the physician may bereduced and the time taken to remove each floater may be greatlyreduced. Consequently, the burden on both the physician and patient maybe diminished. The method 150 may be safer for the patient. Further, themethod 150 may be performed non-invasively. Consequently, the removal ofundesirable features via a laser may be improved.

A method and system for assisting a physician in non-invasively removingundesirable features in an eye have been described. The method andsystems have been described in accordance with the exemplary embodimentsshown, and one of ordinary skill in the art will readily recognize thatthere could be variations to the embodiments, and any variations wouldbe within the spirit and scope of the method and system. Accordingly,many modifications may be made by one of ordinary skill in the artwithout departing from the spirit and scope of the appended claims.

I claim:
 1. A system for performing an ophthalmic procedure on an eyeincluding a lens and a retina, the eye having an optical path from thelens to the retina, the system comprising: a laser; a data processingunit operable to: receive an image of at least a portion of the eye;determine at least one keep out zone based on the image, the at leastone keep out zone including the retina; identify at least oneundesirable feature based on the image; select an undesirable feature ofthe at least one undesirable feature for removal, at least a portion ofthe undesirable feature residing outside of the at least one keep outzone; allow a user to change a size of a keep out zone of the at leastone keep out zone, wherein allowing the user to change the size of thekeep out zone comprises preventing the user from resizing the keep outzone such that the keep out zone is smaller than the retina; a controlunit coupled with the laser and the data processing unit, the controlunit operable to control the laser to perform laser removal of the atleast the portion of the undesirable feature without targeting anyportion of the at least one keep out zone.
 2. The system of claim 1wherein the at least one undesirable feature is at least one vitreousopacity.
 3. The system of claim 1 wherein the control unit is furtheroperable to set a target of the laser within the at least the portion ofthe undesirable feature and fires the laser such that the target iswithin the at least the portion of the undesirable feature.
 4. Thesystem of claim 3 wherein the data processing unit is further operableto track a remaining portion of the undesirable feature in response tothe laser being fired.
 5. The system of claim 1, further comprising animaging system coupled with the control unit and the data processingunit, the imaging system operable to capture the image.
 6. The system ofclaim 1, wherein identifying the at least one undesirable featurecomprises identifying an undesirable feature with an opacity greaterthan an opacity threshold.
 7. The system of claim 1, wherein identifyingthe at least one undesirable feature comprises identifying anundesirable feature with a size greater than a size threshold.
 8. Thesystem of claim 6, wherein identifying the at least one undesirablefeature further comprises identifying an undesirable feature with a sizegreater than a size threshold.
 9. The system of claim 6, wherein theopacity threshold is user provided.
 10. The system of claim 7, whereinthe size threshold is user provided.
 11. The system of claim 1, whereinthe at least one undesirable feature comprises at least two undesirablefeatures, and wherein selecting the undesirable feature of the at leastone undesirable feature for removal comprises ranking the at least twoundesirable features based on size, location, density or shape.
 12. Thesystem of claim 11, wherein selecting the undesirable feature of the atleast one undesirable feature for removal further comprises selectingthe highest ranked undesirable feature of the at least two undesirablefeatures for removal.
 13. The system of claim 1, wherein performinglaser removal by the control unit comprises setting a laser power orlaser application time based on a location targeted.
 14. The system ofclaim 13, wherein performing laser removal by the control unit furthercomprises using a lower laser energy or shorter laser application timefor locations targeted closer to a keep out zone than locations targetedfurther away from the keep out zone.